To perfect an atomic absorption spectrophotometric technique for the determination of chromium in biological samples, using a graphite furnace. This technique will be used in conjunction with existing emission spectrometric techniques in order to measure chromium levels in hair, urine and plasma, including the plasma and urine chromium "response" to a glucose load. To measure the effect of preincubation with insulin and trivalent chromium on the chemotactic activity of polymorphonuclear leukocytes of normal subjects and diabetic children. The combined approaches outlined in #1 and #2 above will be used to investigate the incidence of chromium deficiency with particular respect to the insulin-dependent, non-insulin-dependent, and gestational diabetic.